The present invention relates to a mounting for a pressure line. In particular, the invention relates to a mounting, by means of which a pipe/hose brake line on or in a motor vehicle may be mounted on the brake caliper housing of a disk brake.
Pressure lines with hose portions are used at points where connections in a hydraulic pipeline system have to be flexible. Thus, in the case of a motor vehicle braking system for example, a brake line having a hose portion connects the pipeline fixed to the bodywork with the wheel brake moving with the wheel suspension, e.g. the brake caliper of a disk drake. In this instance, the connection point between hose portion and wheel brake in particular has to satisfy strenuous requirements. Pressures have here to Ae transmitted which may easily be above 100 bar and the brake fluid may reach very high temperatures, even exceeding 100xc2x0 C., during sharp braking, while the connection point is also subject to mechanical stress in the event of spring deflection of the wheel suspension, wherein it is essential that no leaks occur overall.
There is no shortage of proposals in the prior art relating to the construction of this connection point between hose portion and wheel brake. For example, the use of multi-part fittings, as known in principle from DE 30 04 421 C2, DE 35 14 315 C2 or DE 195 44 222 A1, is currently preferred for brake calipers. These stable fittings, with their solid construction, do reduce heat transfer from the brake caliper to the hose portion of the brake line, such that the latter cannot suffer any thermal overload. However, the structure of these fittings is of complex design. Thus, for instance, in the case of the ring fittings known from DE 30 04 421 C2 or DE 35 14 315 C2, in which an annular part connected with the hose portion surrounds a hollow screw concentrically there are at least two seal points requiring appropriate surface machining of the ring fitting and the brake caliper housing. Moreover, complex measures are provided to prevent rotation of the annular part of the fitting relative to the brake caliper housing. Consequently, these fittings alone account for the majority of the production costs for mass-produced brake lines.
The same applies with respect to the fitting known from DE 26 00 725 C2, which is fixed by means of a retaining spring from a spring steel strip.
In additions a construction of the connection point between the hose portion of the brake line and the wheel brake is known DE-OS 1 955 504, DE 42 30 889 A1, in which the hose portion is connected to a curved pipe part by means of a connector, which curved pipe part is in turn provided at the end with a fitting in the form of a union bolt for connection to a wheel brake pressure connection. The end of the pipe part extending through the union bolt comprises a sealing bead, which, when the union bolt is screwed into the pressure connection, is pressed tightly against a conical seal of the pressure connection. With this construction too, the hose portion of the brake line is effectively thermally decoupled from the wheel brake. However, shaking, impacts and vibrations during operation of the motor vehicle and relative movement between wheel suspension and bodywork upon spring deflection result in bending stresses at the pipe part of the brake line, which may lead, after extended use, to leaking of brake fluid at the connection point. The blocks proposed in DE 42 30 889 A1 and formed on the housing of the wheel brake, which accommodate the pipe part of the brake line between their parallel, mutually facing surfaces, are equally deficient.
Finally, DE 299 09 715 U1 discloses a mounting for fixing a corrugated hose. However, in the case of a continuous corrugated hose, the above-described mechanical problems, such as can occur with a pressure line comprising a hose portion and a pipe part, do not arise.
An object of the invention is therefore to provide a mounting of simple design for a pressure line, which assists or ensures secure and reliable connection of the pressure line to a pressure connection.
According to the invention, a mounting for a pressure line, which comprises a pipe part connected with a hose portion by means of a connector, which pipe part may be connected by means of a fitting to a pressure connection of a housing, has a retaining clip having a first portion, by means of which the pressure line may be supported at the connector or the pipe part, and a second portion connected rigidly with the first portion, by means of which second portion the retaining clip may be fixed to the housing via the fitting.
Thus, a mounting of extremely simple construction is provided as a low-cost replacement for the known ring fittings, in which with its first portion the retaining clip absorbs bending and torsional moments acting in particular via the hose portion of the pressure line and with its second portion transmits them on via the fitting into the housing, without the pipe part of the pressure line being exposed to excessive stresses. In other words, the pipe part is by-passed mechanically completely or at least in part by the retaining clip. Consequently, a pressure-tight connection of the pressure line to the housing is lastingly ensured. The first portion of the retaining clip may advantageously serve at the same time to space the hose portion of the pressure line from the housing by a predetermined amount, such that the hose portion is not subject to heat damage. It is additionally advantageous that no separate fastening means have to be provided for the retaining clip, the latter instead being fixed to the housing by its second portion by means of the fitting to be connected anyway to the pressure connection of the housing.
The first portion of the retaining clip may comprise an undercut slot at the end, in which the connector or the pipe part of the pressure line may be secured simply in the manner of a snap connection. Thus, premounting of the retaining clip on the pressure line is also advantageously possible.
In an alternative construction, the first portion of the retaining clip is terminally provided with a slot bounded by arms for receiving an intermediate part fitted to the connector and which can be fixed to the retaining clip in positive and non-positive manner through the plastic bending of the arms. Such a positive and non-positive fixing of the pressure line to the retaining clips in all directions is appropriate if high compulsive forces act on the pressure line, e.g. as a result of pronounced bending of the hose portion and which in the case of the aforementioned snap connection might lead to an unplanned release of the connection.
The intermediate part appropriately has a substantially U-shaped cross-section and is clipped onto an extension of the connector. It Is readily possible to subsequently fit such an intermediate part to the pressure line before the latter is fixed to the retaining clip in the above-described manner. However, it is also conceivable for this intermediate part to be constructed as a ring part, which is engaged in the manner of a sleeve on the extension of the connector before the fitting is fitted to the pipe part of the pressure line.
On the facing sides of the first portion of the retaining clip the arms carry projections or clamps which, accompanied by the plastic beading of the arms, can be pressed into the preferably plastic intermediate part for fixing the latter to the retaining clip. Thus, in a very simple manner a reliable self-closure and force closure is obtained between the intermediate part and the retaining clip.
The retaining clip may be secured with its second portion resiliently between the pressure line fitting and the housing, for which purpose the second portion of the retaining clip is of resilient construction. Owing to this resilient securing of the second portion of the retaining clip, it is possible on the one hand to compensate pipe part contour tolerances without the retaining clip itself gripping the pipe part excessively. On the other hand, the housing does not require any particular machining at the bearing surface for the retaining clip. Furthermore, the elastic construction of the second portion prevents relative movement of the retaining clip in relation to the housing and thus also undesirable retaining clip rattling noises.
There are preferred alternatives for the resilient construction of the second portion of the retaining clip. For example, the second portion of the retaining clip may comprise an opening and develops, at its end remote from the first portion, into a bent flexible tongue, which has a further opening, wherein the fitting of the pressure line extends, when mounted on the housing, through the aligned openings in such a way that the retaining clip is clamped resiliently with its flexible tongue and its second portion between a flange on the fitting and the housing.
The end of the flexible tongue facing the first portion of the retaining clip is preferably offset in the direction of the second portion of the retaining clip and is supported on the second portion, the flexible tongue extending substantially parallel to the second portion of the retaining clip in the area of the opening formed in the flexible tongue, so that the latter can in an advantageous manner engage flat and in a clearly defined form on the flange of the fitting.
On the other hand, the second portion of the retaining clip may comprise an opening for the fitting of the pressure line, wherein flexible arms projecting in the area of the opening are provided on the second portion of the retaining clip, which flexible arms clamp the retaining clip resiliently between a flange on the fitting and the housing when the fitting is mounted on the housing.
The retaining clip may be secured against rotation relative to the housing when the pressure line fitting is mounted on the housing. According to preferred, simple embodiments of this anti-rotation means, the second portion of the retaining clip is located in form-fitting manner in a corresponding recess in the housing, has a locating hole, through which there extends a pin fixed to the housing, or is provided with a bevelled portion, which engages in a recess in the housing.
If the pipe part of the pressure line has to be bent, the first portion conveniently forms a predetermined angle with the second portion of the retaining clip, wherein the retaining clip is preferably provided with profiling for reinforcing purposes in the junction area between the first portion and the second portion.
The retaining clip may consist of spring band steel, such that the retaining clip may take the form of a low-cost bent stamping or precision-blanked part.